Opinion: Aatrox is the ideal Juggernaut
Ignoring anything you might feel about his rework (and the fact it just happened to coincide with the only time he's ever been top tier thanks to changes to things besides himself), the new Aatrox is, in my opinion the ideal example of a juggernaut.
What do mean? Well, he still follows the trend of having high damage output and survivability, but with one striking difference that makes him far and beyond the best example of the class: he's not extremely easy.
(not including ones Riot arbitrarily added to the list with no changes to their kits) The original juggernauts-- Garen, Darius, and Nasus-- have the crutch that is mechanical ease of play. They rely mainly on their stats to perform because mechanical skill has nothing to do with it. This means they generally dominate for the majority of players (those gold and below, and norms), but generally stagger at higher levels of play. And I really don't think that's healthy for the game as a whole. Having no choice but to either counter-pick (roughly half the time) or play so safe you don't really get to play for half the game, just turns people off.
I think that the large-area+sweet-spot swing that Aatrox has should become a sort of commonality among all the juggernats. Darius's Q somewhat resembles it, but he still mainly stacks his passive with autos. He uses an AXE, for Pete's sake. It'd make more sense for his main damage to come from quick successions of wide swings than anyone else. Garen and Nasus also use comically large weapons because they're comically large dudes. It'd make way more sense for them to generally cleave through enemies than the heavy single-target things they do. And I know Garen's E is also similar, but it's essentially a Karthus E that blinds you.
I'm not saying they should all have exactly the same ability as Aatrox, but a wide swing with a sweet spot is a general enough idea for an attack to make it unique for each of them, while still playing to their other abilities. If they were all given this kind of ability, with its increased range but ability to be countered with proper positioning/dashing, they could be adjusted to perform average at all levels of play.